Archive
Posts from 2005
Using the Linux ltrace utility to trace library calls
While debugging an application on a Linux server this week, I needed to view the library calls (specifically malloc and free) that were being called by a process. This was super easy to do with the Linux ltrace(1) utility: ltrace(1) also allows you to selectively trace library calls when executed with the "-e" option and a set of calls to trace: If you need to view the library calls from a live process, you can use ltrace(1)'s "-p" option: This is a super cool utility, and is invaluable tool for debugging application problems on Linux systems.
$ read more →Recovering root passwords with Fedora Core
I performed a Fedora core 4 installation today, and for some reason the root password I typed in during the installation got munged (or I typed it incorrectly two times). Since Fedora Core uses grub as a boot loader, I was able to recover from this situation relatively quickly. To get to a shell where I could use the passwd(1) utility or vi(P) to change the password, I first needed to reboot the box to get to the grub menu. Once I was greeted with the grub menu, I used the up and down arrow keys to select a kernel, and then hit the 'e' key to edit the boot paramaeters…
$ read more →Comparing SOA records with dig
Whiel reading through the dig documentation today I came across the "nssearch" option: This nifty little option can be used to view the SOA record maintained by all servers authoritative for a domain. If you choose to avoid using AXFR and manually update zone files, this option could be extremely useful.
$ read more →What is this mDNSResponder process?
While reviewing the running processes on my Linux desktop, I noticed a process named mDNSResponder. I have seen this process numerous times on my OS X desktops, but have never taken the time to determine what function it served. Being the curious guy I am, I read through the mDNSResponder(1) manual page, and found the following description: "The mDNSResponder daemon publishes and browses available services on a link according to the IETF Zeronconf (aka "Rendezvous") draft standard. Only one instance of mDNSResponder needs to run on a host…
$ read more →PCI Express and DDR2 -- worth the money?
While ignoring my own advice and reading various Mac rumor sites today, I saw that the next generation Powermacs may ship with DDR2 memory and PCI express video cards. Being the geek I am, I wandered off to see how much throughput could be achieved with each technology. I started my knowledge quest by reading PCSTATS PCI Express tutorial, and was blown away by the potential of PCI Express. Not only does PCI express move considerably more data than PCI (250MB/s vs…
$ read more →